Researchers have found what they believe is the key to understanding why the human brain is larger and more complex than that of other animals. The human brain, with its unequaled cognitive capacity, evolved rapidly and dramatically. "We wanted to know why," says James Sikela, PhD, who headed the international research team that included researchers from the University of Colorado School of Medicine, Baylor College of Medicine and the National Institutes of Mental Health. "The size and cognitive capacity of the human brain sets us apart. But how did that happen?"